An old/new idea for reducing exposure to x-rays.

In 1925 the patient's exposure to x-radiation was reduced 50 percent by the application of emulsion to both sides of the dental film. Another similar reduction is possible when the layers of emulsion are once again doubled. The authors have rediscovered this idea and tested it. A double film packet containing films which are hinged on one side for proper reorientation after developing was produced. The films were exposed to half the radiation given to normal packets. It was found that density, contrast, and definition were all comparable to normal exposures when allowances were made for an additional layer of blue-tinted film base. In addition to reduced exposure to x-rays, the folded-film technique gives a second view of the exposed area. An underexposed view is obtained by viewing either side of the folded film alone. This underexposed view offers some details not seen on fully exposed films.

Low-dose bleomycin lung.

A patient with retroperitoneal diffuse histiocytic lymphoma treated with combination chemotherapy developed breathlessness and fever after receiving 30 units of bleomycin. At this stage pulmonary function tests were impaired and gallium scanning showed diffuse uptake in both lungs although a chest X-ray film was normal. Bleomycin treatment was stopped but interstitial infiltrates appeared on subsequent chest X-ray films. Open lung biopsy showed histologic changes of bleomycin toxicity. After treatment with prednisone, the patient felt well and was shown to have a normal gallium scan ad normal respiratory function studies.

Ultrastructural changes in intersegmental cuticle during rotation of the terminal abdominal segments in a mosquito.

The terminal abdominal segments of male Aedes aegypti rotate 180 degrees within 24 hr after adult emergence, rotation occurring in the intersegmental membrane between abdominal segments VII and VIII. The ultrastructure of this rotating membrane is compared with non-rotating intersegmental membranes at different developmental stages. The deposition of cuticle in both the rotating and non-rotating intersegments appears ultrastructurally similar, and follows the sequential pattern described for the insects. Shortly after adult emergence, however, disruptive changes occur in the membrane cuticle that are more pronounced in non-rotating intersegments. This disruption occurs initially 1 hr after adult emergence and becomes maximal within 3 hr. Disruption appears to occur by the addition of fluid to the cuticle and results in a ten-fold increase in cuticle thickness in non-rotating intersegments but only a two-fold increase in thickness in the rotating intersement. While in the disrupted condition, the non-rotating intersegmental membranes become extensively folded whereas the cuticle in the rotating intersegment becomes stretched. During rotation, strain forces in the rotating intersegment result in a reorientation of microfibers in the cuticle from parabolic to parallel. This reorientation is presumably brought about by plastic flow.

Dynamic tomography.

Dynamic tomography is a radiographic procedure that allows details in a thin layer within the patient to be examined. This layer can be moved at will throughout the patient. Thus, details lying in an infinite number of layers can be scrutinized one layer at a time. Eight underexposed radiographs are made under rigid controls. Each film receives one fourth of a normal exposure. The "in focus" layer of details is about 0.5 mm. thick. Various future applications of the technique are discussed.

Ultrastructure of the atypic muscles associated with terminalial inversion in male Aedes aegypti (L).

Two sets of opposed, crossed muscles are present in the rotating region of the abdomen in male A. aegypti. These muscles undergo changes during rotation of the genitalia that suggest they function as the driving force for rotation. During this rotation, one muscle of each set contracts and the opposed one becomes elongated. The contracting muscles are atypic physiologically. They contract from 300 mum to about 69 mum, and this requires a period of 18 to 24 hours. They shorten only once and those muscle fibers still present after the completion of rotation remain in a contracted condition at least for two weeks. The elongated muscles never shorten; they become stretched to approximately 2.5 times their original length and disappear soon after rotation is completed.